The present invention relates to methods of establishing multi-point contact with insulated conductors, and electrical connectors for use in conjunction with high energy rate supply circuits where frequent connections are required to be made between the circuit and the end portions of one or more insulated conductor wires.
Smotherman U.S. Pat. No. 3,391,379 (issued July 2, 1968) describes, among other things, the desirability of establishing good multi-point contact with insulated conductors that are thus connected with high energy rate supply circuits. While the Smotherman teachings may be applied to different types of situations; one particular type of application of equipment and apparatus in which it is extremely desirable to consistently establish proper contact is taught, for example, in Baldwin U.S. Pat. No. 3,407,468 which issued Oct. 29, 1968. These two patents are assigned to the assignee of the present application, and the entire disclosures of said Smotherman and Baldwin patents are incorporated herein by reference.
I have determined that when prior methods and constructions are utilized, connector elements must be replaced with relative frequency. It is believed that at least part of this problem is because prior connectors actually make good contact in only a few places along a conductor. Then, when high current surges are applied (e.g., 400 to 500 amperes in 4 to 6 milliseconds); an arc may be established that can destroy the segment of conductor adjacent to the connector and also destroy one more contact points; or teeth on the connector. This destruction of a connector contact point more frequently appears in connection with a pitted or burned spot on the connector. It has seemed that second, and then third, burn spots have developed relatively soon after the first "burn"; and three "blows" or burns have usually been taken as an indication that a new connector must be provided.
Prior arrangements have used soldering or brazing techniques for making permanent connections between a power supply lead and a connector. This in turn has necessitated the use of a relatively large amount of time for replacement of connectors that have been damaged due to arcing, pitting, or any other reason.
In high production situations, it often is desirable to provide current surges to devices having conductors of a given size within a predetermined range of sizes. Prior connector arrangements have been somewhat deficient in ability to make good electrical connections with a wide range of wire sizes. For example, when a prior connector construction was relatively reliable for making connections to a first conductor size; if connections then were attempted with a second conductor size that differed too much from the first size, arcing might occur that would destroy the connector jaw. Then the difficulty associated with replacing connector surfaces would again be apparent. Of course, the difficulty of replacing connector surfaces would also be apparent when changing connector members so as to better accommodate different sizes of conductors.
When prior connection means are used, a build-up of magnet wire insulation residue may occur on connector jaws and eventually lead to relatively bad electrical connection between the contact jaws and the conductor portion of a length of insulating magnet wire. When this occurs, arcing may occur between connector jaws and the magnet wire with the result that burning and pitting of the contact jaws may take place. It will be appreciated that the magnet wire also may be vaporized by the arcing action with the result that a portion of the lead wire is destructed. Even more importantly, when arcing occurs, the surge of energy delivered from a power supply may be dissipated during destruction of the magnet wire segment and a desirable coil transforming operation (as described for example in the referenced Baldwin patent) may not take place.
Accordingly, it would be desirable to provide an improved method of establishing a secure and positive electrical connection with a minimum amount of damage to conductor leads. Moreover, it would be desirable to provide an improved structural arrangement whereby, even if connectors eventually deteriorate, the contact portions of the connectors may be rapidly and quickly replaced with readily available structural members in an inexpensive and facile manner. It would even be more desirable to provide an arrangement whereby good electrical connection may be assured between a connector and the conductive portion of an insulated section of a range of magnet wire sizes. Desirably, the useful life of contact members would be increased as compared to prior arrangements, and magnet wire insulation on a conductor would be extruded away from portions of a conductor so as to avoid build-up of stripped insulation on a connector surface.